With a maximum weight of 165 g, the Petzl Sirocco Helmet sets a new standard for lightness. The one-piece construction minimizes helmet weight while retaining excellent impact resistance, due to the mechanical properties of expanded polypropylene (EPP). The textile adjustment system also contributes to its lightness. This helmet comes with a new magnetic buckle which allows the chinstrap to be fastened with one hand. The SIROCCO helmet also has excellent ventilation distributed around the helmet.